1. Field of Invention
This invention relates to devices and methods directed to aligning a printhead ejector module by a vernier technique.
2. Description of Related Art
The photocopier industry modularizes a variety of consumable components as replaceable and disposable cartridges, categorized by function, employed in the photocopier machine. Each of these cartridges to be inserted or removed from the machine constitutes a replaceable module, also known in the industry as a customer replaceable unit (CRU), for example, described in U.S. Pat. No. 5,809,375 to Owens, Jr. et al.
The photocopier industry employs inkjets as ejector modules disposed in a full-width array (FWA) print bar, for example, described in U.S. Pat. No. 5,801,727 to Torpey. The ejector modules receive fluid ink from a reservoir (typically a tank module) through a manifold. Various ejector modules employ a variety of techniques for releasing controllable quantities of ink onto a medium, including thermal inkjets (TIJ), piezoelectric inkjets (PIJ) and micro-electro-mechanical-system inkjets (MEMSJet). In particular, TIJ ejector modules are manually replaceable by the user. The ink is ejected through nozzles onto the medium upon command, but is otherwise retained within the ejector module by surface tension and by differential pressure, whereby the internal ejector pressure can be lower than ambient to which the ink is exposed.